VEHICLE
A vehicle includes: a vehicle body; one or more turn wheels turnable to right and left; turn wheel support unit; and controller. The turn wheel support unit includes: a supporting member that rotatably supports the one or more turn wheels; and a turning actuator configured to apply a turning torque to the supporting member. The controller is configured to determine a target lean angle, determine a first type control value by using a difference between the target lean angle and a lean angle, and determine the target turning torque by using one or more control values including the first type control value. Where the first type control value indicates a torque that causes the supporting member to turn in a direction opposite to a target direction that is a rotational direction to rotate the vehicle body in its width direction so that the lean angle approaches the target lean angle.
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This specification relates to a vehicle which turns by leaning its vehicle body.
BACKGROUND ARTVehicles of which vehicle bodies lean during turning are known. A variety of techniques have been proposed for smoothly leaning a vehicle body to the inside of turn. For example, a technique has been proposed that, when a driver begins to operate a handlebar, changes a steering angle of a steered wheel toward an opposite direction to a rotational direction of handlebar. This technique causes a turn in a direction opposite to a direction intended by the driver, and a centrifugal force generated by the turn causes the vehicle body to lean to the inside of the turn intended by the driver. Accordingly, it is possible to smoothly lean the vehicle body to the inside of the turn.
PRIOR ART DOCUMENTPatent Document
Patent Document 1 Japanese Laid-Open Patent Publication No. 2013-23166
SUMMARY OF THE INVENTION Problems to be Solved by the InventionIn the above document, a target value of steering angle is determined by using a steering wheel angle that is a rotational angle of handlebar. A lean angle of the vehicle body, and the steering angle can change independently. There has been insufficient effort to improve driving stability of vehicle in which the lean angle of vehicle body, and the direction of wheel change in this manner.
This specification discloses the technique of improving driving stability of vehicles.
Means for Solving the ProblemsThe technique disclosed herein can be implemented as any of application examples listed below.
APPLICATION EXAMPLE 1A vehicle including:
a vehicle body;
N (N is an integer equal to or larger than 2) wheels including one or more turn wheels turnable to right and left relative to a forward movement direction of the vehicle, the N wheels including at least one front wheel and at least one rear wheel;
a lean angle sensor configured to measure a lean angle in a width direction of the vehicle body;
an operation input unit configured to be handled to input an operation amount indicative of a turning direction and a degree of turn;
a turn wheel support unit that supports the one or more turn wheels, and
a controller,
wherein the turn wheel support unit comprises:
-
- a supporting member that rotatably supports the one or more turn wheels;
- a turning device that supports the supporting member turnably to right and left relative to the vehicle body; and
- a turning actuator configured to apply to the supporting member a turning torque for turning the supporting member, and
wherein a lean angle targeted by the vehicle body is referred to as a target lean angle;
a difference between the target lean angle and the lean angle of the vehicle body is referred to as a lean angle difference; and
a target torque of the turning actuator is referred to as a target turning torque,
wherein the controller is configured to:
-
- determine the target lean angle by using one or more parameters including the operation amount;
- determine a first type control value indicative of a first torque by using the lean angle difference, the first torque causing the supporting member to turn in a direction opposite to a target direction that is a rotational direction to rotate the vehicle body in its width direction so that the lean angle approaches the target lean angle, the target direction being either a right direction or a left direction;
- determine the target turning torque by using one or more control values including the first type control value; and
- control the turning actuator according to the target turning torque.
According to this configuration, the first type control value used to determine the target turning torque is determined to be a value indicative of the first torque causing the supporting member to rotate in a direction opposite to the target direction, and therefore the turning of the supporting member by the turning torque allows the lean angle of the vehicle body to readily approach the target lean angle. In addition, the first type control value is determined by using the lean angle difference, which is a difference between the target lean angle and the lean angle of the vehicle body, and therefore is determined to be a value appropriate for the lean angle difference. Therefore, the driving stability of the vehicle can be improved.
APPLICATION EXAMPLE 2The vehicle according to Application Example 1,
wherein a ratio of a magnitude of the first torque indicated by the first type control value to a magnitude of the lean angle difference is referred to as an angle difference-torque ratio, and
wherein the controller is configured to determine the first type control value so that the angle difference-torque ratio changes according to a vehicle velocity.
According to this configuration, the angle difference-torque ratio changes according to a vehicle velocity, and thus the first type control value appropriate for the vehicle velocity is determined. Therefore, the driving stability of the vehicle can be improved.
APPLICATION EXAMPLE 3The vehicle according to Application Example 2,
wherein the controller is configured to determine the first type control value so that the angle difference-torque ratio when a magnitude of the vehicle velocity is smaller than a first threshold value is larger than the angle difference-torque ratio when the magnitude of the vehicle velocity is larger than the first threshold value.
According to this configuration, the first type control value is determined so that when the magnitude of the vehicle velocity is smaller than the first threshold value, the angle difference-torque ratio is larger as compared to when the magnitude of the vehicle velocity is larger than the first threshold value, and therefore it is possible to suppress delayed change in the lean angle of the vehicle body when the magnitude of the vehicle velocity is smaller.
APPLICATION EXAMPLE 4The vehicle according to any one of Application Examples 1 to 3,
wherein the controller is configured to:
-
- determine a second type control value indicative of a second torque by using an angular velocity of the lean angle of the vehicle body, the second torque causing the supporting member to turn in a direction of change in the lean angle out of the right direction and the left direction; and
- determine the target turning torque by using two or more control values including the first type control value and the second type control value.
According to this configuration, the second type control value indicative of the second torque causing the supporting member to turn in the direction of change in the lean angle is determined by using the angular velocity of the lean angle, and the target turning torque is determined by using two or more control values including the first type control value and the second type control value, which can result in improved driving stability of the vehicle.
APPLICATION EXAMPLE 5The vehicle according to Application Example 4,
wherein a ratio of a magnitude of the second torque indicated by the second type control value to a magnitude of the angular velocity of the lean angle is referred to as an angular velocity-torque ratio, and
wherein the controller is configured to determine the second type control value so that the angular velocity-torque ratio changes according to the vehicle velocity.
According to this configuration, the angular velocity-torque ratio changes according to the vehicle velocity, and thus the second type control value appropriate for the vehicle velocity is determined. Therefore, the driving stability of the vehicle can be improved.
APPLICATION EXAMPLE 6The vehicle according to Application Example 5,
wherein the controller is configured to determine the second type control value so that the angular velocity-torque ratio when a magnitude of the vehicle velocity is smaller than a second threshold value is larger than the angular velocity-torque ratio when a magnitude of the vehicle velocity is larger than the second threshold value.
According to this configuration, the second type control value is determined so that when the magnitude of the vehicle velocity is smaller than the second threshold value, the angular velocity-torque ratio is larger as compared to when the magnitude of the vehicle velocity is larger than the second threshold value, and therefore unintended change in the lean angle can be suppressed.
APPLICATION EXAMPLE 7The vehicle according to any one of Application Examples 1 to 6,
wherein the controller is configured to:
-
- determine a third type control value indicative of a third torque by using an angular acceleration of the lean angle of the vehicle body, the third torque causing the supporting member to turn in a direction of change in angular velocity of the lean angle out of the right direction and the left direction; and
- determine the target turning torque by using two or more control values including the first type control value and the third type control value.
According to this configuration, the third type control value indicative of the third torque causing the supporting member to turn in the direction of change in the angular velocity of the lean angle is determined by using the angular acceleration of the lean angle, and the target turning torque is determined by using two or more control values including the first type control value and the third type control value, which can result in improved driving stability of the vehicle.
APPLICATION EXAMPLE 8The vehicle according to Application Example 7,
wherein a ratio of a magnitude of the third torque indicated by the third type control value to a magnitude of the angular acceleration of the lean angle is referred to as an angular acceleration-torque ratio, and
wherein the controller is configured to determine the third type control value so that the angular acceleration-torque ratio changes according to a vehicle velocity.
According to this configuration, the angular acceleration-torque ratio changes according to the vehicle velocity, and thus the third type control value appropriate for the vehicle velocity is determined. Therefore, the driving stability of the vehicle can be improved.
APPLICATION EXAMPLE 9The vehicle according to Application Example 8,
wherein the controller is configured to determine the third type control value so that the angular acceleration-torque ratio when a magnitude of the vehicle velocity is smaller than a third threshold value is larger than the angular acceleration-torque ratio when a magnitude of the vehicle velocity is larger than the third threshold value.
According to this configuration, the third type control value is determined so that when the magnitude of the vehicle velocity is smaller than the third threshold value, the angular acceleration-torque ratio is larger as compared to when the magnitude of the vehicle velocity is larger than the third threshold value, and therefore unintended change in the lean angle can be suppressed.
APPLICATION EXAMPLE 10The vehicle according to any one of Application Examples 1 to 9, including
a lean actuator configured to apply to the vehicle body a lean torque for controlling the lean angle of the vehicle body.
According to this configuration, the lean angle can be changed properly by using the lean torque.
APPLICATION EXAMPLE 11The vehicle according to any one of Application Examples 1 to 10,
wherein the N wheels include three or more wheels including a pair of wheels spaced apart from each other in the width direction;
wherein the vehicle comprises:
-
- a lean device configured to lean the vehicle body in the width direction; and
- a lock device configured to lock the lean device, and
wherein the controller is configured to:
-
- if a magnitude of the vehicle velocity is equal to or larger than a fourth threshold value,
- cause the lock device to unlock the lean device, and
- control the turning actuator according to the target turning torque, and
- if a magnitude of the vehicle velocity is smaller than the fourth threshold value,
- cause the lock device to lock the lean device, and
- cause the turning actuator to output the turning torque that causes the supporting member to turn in the target direction.
- if a magnitude of the vehicle velocity is equal to or larger than a fourth threshold value,
According to this configuration, the lean device is locked by the lock device during lower velocity, and therefore the lean angle is suppressed from becoming unstable.
It should be noted that the techniques disclosed in this specification can be realized in a variety of aspects, for example, a vehicle, a vehicle controller, a vehicle control method, etc.
In this embodiment, this vehicle 10 is a small single-seater vehicle. The vehicle 10 (
The vehicle body 90 (
The vehicle body 90 further includes a seat 11 attached onto the bottom portion 20b, an accelerator pedal 45 and a brake pedal 46 located on the front direction DF side of the seat 11, a controller 100 attached onto the bottom portion 20b, a battery 120, a front wheel support device 41 attached to the end in the upward direction DU side of the front portion 20a, and a shift switch 47 attached to the front wheel support device 41. Other members (e.g. roof, headlight, etc.) may be attached to the main body 20 although they are not shown in the figures. The vehicle body 90 includes the members attached to the main body 20.
The shift switch 47 is a switch for selecting a driving mode of the vehicle 10. In this embodiment, it is possible to select a mode from among four driving modes, “drive,” “neutral,” “reverse,” and “parking.” The “drive” mode is a mode for moving forward by driving the drive wheels 12L, 12R, the “neutral” mode is a mode in which the drive wheels 12L, 12R can rotate freely, the “reverse” mode is a mode for moving backward by driving the drive wheels 12L, 12R, the “parking” mode is a mode in which at least one wheel (e.g. rear wheels 12L, 12R) cannot rotate. The “drive” and “neutral” modes are typically used when the vehicle 10 moves forward.
The front wheel support device 41 (
The vehicle 10 is equipped with a steering wheel 41a that is rotatable to right and left. The steering wheel 41a is an example operation input unit that is configured to be handled to input a turning direction and a degree of turn. The rotational direction of the steering wheel 41a (right or left) relative to a predetermined straight movement direction represents a turning direction desired by the user. The rotational angle of the steering wheel 41a relative to the straight movement direction (hereinafter sometimes referred to as “steering wheel angle”) represents a degree of turn desired by the user. In this embodiment, “steering wheel angle=0” indicates straight movement, “steering wheel angle>0” indicates a right turn, and “steering wheel angle<0” indicates a left turn. In this manner, the positive and negative signs of steering wheel angle represent the turning direction. The absolute value of steering wheel angle represents the degree of turn. Such a steering wheel angle is an example operation amount that represents the turning direction and the degree of turn input to the steering wheel 41a.
In this embodiment, secured to the steering wheel 41a is a supporting rod 41ax which extends along the rotational axis of the steering wheel 41a. The supporting rod 41ax is coupled to the front wheel support device 41 rotatably about its rotational axis.
The wheel angle AF (
The steering motor 65 is controlled by the controller 100 (
An angle CA shown in
Also, as shown in
The two rear wheels 12L, 12R (
The first support portion 82 (
The right rear wheel 12R (
The link mechanism 30 (
In this embodiment, the link mechanism 30 has bearings for rotatably coupling link members. For example, a bearing 38 rotatably couples the lower lateral link member 31D to the center longitudinal link member 21, and a bearing 39 rotatably couples the upper lateral link member 31U to the center longitudinal link member 21. Other portions rotatably coupling link members are also provided with bearings although they are not specifically described here.
The lean motor 25, which is an example actuator for actuating the link mechanism 30, is an electric motor having a stator and a rotor, in this embodiment. One of the stator or rotor of the lean motor 25 is secured to the center longitudinal link member 21, and the other is secured to the upper lateral link member 31U. The rotational axis of the lean motor 25 is the same as that of the bearing 39, and is located at the center of the vehicle 10 in its width direction. When the rotor of the lean motor 25 rotates relative to the stator, the upper lateral link member 31U is tilted with respect to the center longitudinal link member 21. This causes the vehicle 10 to lean. Hereinafter, the torque generated by the lean motor 25 may be referred to as lean torque. The lean torque is for controlling the lean angle of the vehicle body 90.
As shown in the rear view of
In
A control angle Tc of the link mechanism 30 is also shown in
As shown in
The lateral link member 31U is connected via the longitudinal link members 33L, 33R and the motors 51L, 51R to the wheels 12L, 12R. The center longitudinal link member 21 is connected via the first support portion 82 and a suspension system 70 (described later) to the vehicle body 90. The lean motor 25 applies to the members 31U and 21 a force that changes the relative position between the member 31U connected to the wheels 12L, 12R and the member 21 connected to the vehicle body 90 (in this case, a torque that changes the orientation of the member 21 relative to the member 31U).
In this manner, when the ground GLx is inclined, the magnitude of the lean angle T of the vehicle body 90 can differ from that of the control angle Tc of the link mechanism 30.
In addition, the vehicle 10 (
In this embodiment, the main body 20 is coupled to the rear wheel support 80 via the suspension system 70 and the connector rod 75, as shown in
The connector rod 75 is a rod which extends in the front direction DF as shown in
In this manner, the main body 20 (and thus the vehicle body 90) is coupled to the rear wheel support 80 via the suspension system 70 and the connector rod 75. The vehicle body 90 can rotate in its width direction through the extension/retraction of the suspensions 70L, 70R. The roll axis AxR of
In
The vehicle body 90 can rotate in the width direction of the vehicle 10 relative to the vertically upward direction DU (and thus the ground GL) through a rotation by the rear wheel support 80 and a rotation by the suspension system 70 and connector rod 75. The rotation of the vehicle body 90 in its width direction achieved in an integrated manner in the overall vehicle 10 may be referred to as roll. A roll can be also caused by a deformation of the members of the vehicle 10, such as the vehicle body 90 and the tires 12Rb, 12Lb. It should be noted that typically, the rotation about the roll axis AxR is temporary, and its degree is smaller than that of rotation through the lean device 89.
A gravity center 90c is shown in
As shown, the gravity center 90c is located on the downward direction DD side of the roll axis AxR. Therefore, if the vehicle body 90 oscillates about the roll axis AxR, an excessive increase in amplitude of oscillation can be suppressed. In this embodiment, the battery 120, which is a relatively heavy element among the elements of the vehicle body 90 (
A first force F1 in the figure is a centrifugal force acting on the vehicle body 90. A second force F2 is a gravity acting on the vehicle body 90. Where the mass of the vehicle body 90 is m (kg), the acceleration of gravity is g (about 9.8 m/s2), the lean angle of the vehicle 10 relative to the vertical direction is T (degrees), the velocity of the vehicle 10 during turning is V (m/s), and the turning radius is R (m). The first force F1 and the second force F2 are expressed in Equations 1 and 2, respectively:
F1=(m*V2)/R (Equation 1)
F2=m*g (Equation 2)
Where * represents a multiplication sign (hereinafter the same shall apply).
In addition, a force F1b in the figure is a component of the first force F1 in a direction perpendicular to the vehicle upward direction DVU. A force F2b is a component of the second force F2 in a direction perpendicular to the vehicle upward direction DVU. The force F1b and the force F2b are expressed in Equations 3 and 4, respectively:
F1b=F1*cos(T) (Equation 3)
F2b=F2*sin(T) (Equation 4)
Where “cos( )” is a cosine function, and “sin( )” is a sine function (hereinafter the same shall apply).
The force Flb is a component which causes the vehicle upward direction DVU to be rotated to the left direction DL side while the force F2b is a component which causes the vehicle upward direction DVU to be rotated to the right direction DR side. When the vehicle 10 continues to turn stably with the lean angle T (and furthermore the velocity V and turning radius R) maintained, the relationship between F1b and F2b is expressed in the following equation 5:
F1b=F2b (Equation 5)
By substituting Equations 1-4 as discussed above into Equation 5, the turning radius R is expressed in Equation 6:
R=V2/(g*tan(T)) (Equation 6)
Where “tan( )” is a tangent function (hereinafter the same shall apply).
Equation 6 is established independently of the mass m of the vehicle body 90. Equation 6a below, which is obtained by substituting “T” in Equation 6 with a parameter Ta (in this case, absolute value of lean angle T) representing the magnitude of the lean angle without distinction between the right and left directions, is true regardless of the lean direction of the vehicle body 90:
R=V2/(g*tan(Ta)) (Equation 6a)
As shown in
AF=arctan(Lh/R) (Equation 7)
Where “arctan( )” is an inverse function of tangent function (hereinafter the same shall apply).
It should be noted that there are a variety of difference between the actual behavior of the vehicle 10 and the simplified behavior in
When the vehicle 10 leans to the right direction DR side during its forward movement as shown in
In addition, the behavioral stability of the vehicle 10 is improved because the forces F1b, F2b (
Furthermore, in this embodiment, when the vehicle body 90 leans, the front wheel 12F is subject to a force that rotates the wheel angle AF to the lean direction independently of the trail Lt.
In this embodiment, the front wheel support device 41 is secured to the vehicle body 90. Therefore, when the vehicle body 90 leans, the front wheel support device 41 leans along with the vehicle body 90, and thus the rotational axis Ax2 of the front wheel 12F will also lean to the same direction in a similar fashion. When the vehicle body 90 of the moving vehicle 10 leans to the right direction DR side, the front wheel 12F, which rotates about the rotational axis Ax2, is subject to a torque Tqx that causes the front wheel 12F to lean to the right direction DR side. This torque Tqx includes a component of force that acts to lean the front wheel 12F about the front axis Ax3 to the right direction DR. Such a movement of a rotating object when an external torque is applied to the object is known as precession movement. For example, the rotating object turns about an axis perpendicular to the rotational axis and the axis of the external torque. In the example of
The above description refers to the case where the vehicle 10 leans to the right direction DR side. Similarly, the direction D12 of the front wheel 12F (i.e. wheel angle AF) turns to the left direction DL side following the lean of the vehicle body 90 when the vehicle 10 leans to the left direction DL side.
When the torque of the steering motor 65 is smaller, the front wheel support device 41 supports the front wheel 12F as follows. That is, the front wheel 12F can turn to right and left relative to the vehicle body 90 following a change in lean of the vehicle body 90 independently of information input to the steering wheel 41a. For example, even if the steering wheel 41a is maintained in the predetermined direction corresponding to the straight movement, the front wheel 12F can turn to right following a change in the lean angle T when the lean angle T of the vehicle body 90 changes toward right (i.e. the wheel angle AF can change toward right). The front wheel support device 41 supporting the front wheel 12F in this manner may be restated as follows. That is, the front wheel support device 41 supports the front wheel 12F turnably to right and left relative to the vehicle body 90 following a change in lean of the vehicle body 90 so that the wheel angle AF of the front wheel 12F for a single operation amount input to the steering wheel 41a is not restricted to a single wheel angle AF.
As shown in
In addition, the connection 50 allows a moderate change in the orientation of the front fork 17 (and thus front wheel 12F) relative to that of the steering wheel 41a. In this manner, the connection 50 connects loosely the steering wheel 41a and the front fork 17. Such a connection 50 allows the front wheel 12F to turn to right and left relative to the vehicle body 90 following a change in lean of the vehicle body 90 independently of the steering wheel angle input to the steering wheel 41a when the torque of the steering motor 65 is smaller. Therefore, the driving stability is improved because the wheel angle AF can change to an angle appropriate for the lean angle T.
A2. Control of Vehicle 10:
The vehicle velocity sensor 122 is a sensor for detecting a vehicle velocity of the vehicle 10. In this embodiment, the vehicle velocity sensor 122 is attached on the lower end of the front fork 17 (
The steering wheel angle sensor 123 is a sensor for detecting an orientation of the steering wheel 41a (i.e. steering wheel angle). In this embodiment, the steering wheel angle sensor 123 is attached to the supporting rod 41ax secured to the steering wheel 41a (
The wheel angle sensor 124 is a sensor for detecting a wheel angle AF of the front wheel 12F. In this embodiment, the wheel angle sensor 124 is attached to the steering motor 65 (
The vertical direction sensor 126 is a sensor for determining the vertically downward direction DD. In this embodiment, the vertical direction sensor 126 includes an acceleration sensor 126a, a gyroscope sensor 126g, and a control unit 126c.
The acceleration sensor is a sensor that detects acceleration in any direction, for example, triaxial accelerometer. Hereinafter, a direction of acceleration detected by the acceleration sensor 126a will be referred to as detected direction. With the vehicle 10 stopped, the detected direction is the same as the vertically downward direction DD. That is, a direction opposite to the detected direction is the vertically upward direction DU.
The gyroscope sensor 126g is a sensor that detects angular acceleration about a rotational axis in any direction, for example, triaxial angular accelerometer.
The control unit 126c is a device that uses a signal from the acceleration sensor 126a and a signal from the gyroscope sensor 126g to determine the vertically downward direction DD. For example, the control unit 126c is a data processor including a computer.
The acceleration sensor 126a and the gyroscope sensor 126g may be secured to a variety of members of the vehicle 10. For example, the acceleration sensor 126a and the gyroscope sensor 126g are secured to the same member. In the embodiment of
When the vehicle 10 is moving, the detected direction can be displaced from the vertically downward direction DD in response to the movement of the vehicle 10. For example, the detected direction is displaced so that it is tilted toward the back direction DB side from the vertically downward direction DD if the vehicle 10 accelerates during its forward movement. The detected direction is displaced so that it is tilted toward the front direction DF side from the vertically downward direction DD if the vehicle 10 decelerates during its forward movement. The detected direction is displaced so that it is tilted toward the right direction DR side from the vertically downward direction DD if the vehicle 10 turns to left during its forward movement. The detected direction is displaced so that it is tilted toward the left direction DL side from the vertically downward direction DD if the vehicle 10 turns to right during its forward movement.
The control unit 126c of the vertical direction sensor 126 uses the vehicle velocity V detected by the vehicle velocity sensor 122 to calculate the acceleration of the vehicle 10. Then, the control unit 126c uses the acceleration to determine the displacement of the detected direction from the vertically downward direction DD due to the acceleration of the vehicle 10 (e.g. the displacement of the detected direction toward the front direction DF or back direction DB is determined). In addition, the control unit 126c uses the angular acceleration detected by the gyroscope sensor 126g to determine the displacement of the detected direction from the vertically downward direction DD due to the angular acceleration of the vehicle 10 (e.g. the displacement of the detected direction toward the right direction DR or left direction DL is determined). The control unit 126c uses the determined displacement to modify the detected direction, and thereby determines the vertically downward direction DD. In this manner, the vertical direction sensor 126 can determine the vertically downward direction DD properly under a variety of driving conditions of the vehicle 10.
The control unit 126c outputs vertically downward direction information indicating the determined vertically downward direction DD. The vertically downward direction information indicates the vertically downward direction DD relative to a predetermined reference direction of the vertical direction sensor 126. In this embodiment, the vertical direction sensor 126 is secured to the vehicle body 90 (more specifically, the main body 20). Accordingly, the correspondence relationship between the vehicle upward direction DVU of the vehicle body 90 and the reference direction of the vertical direction sensor 126 is predetermined (referred to as sensor direction relationship). This sensor direction relationship can be used to convert the vertically downward direction DD indicated by the vertically downward direction information to the vertically downward direction DD relative to the vehicle upward direction DVU of the vehicle body 90.
The accelerator pedal sensor 145 is attached to the accelerator pedal 45 (
Each sensor 122, 123, 124, 145, 146 is configured using a resolver or encoder, for example.
The controller 100 includes a main control unit 110, a drive device control unit 300, a lean motor control unit 400, a steering motor control unit 500, and a lock motor control unit 600. The controller 100 operates with electric power from the battery 120 (
The processor 110p of the main control unit 110 receives signals from the sensors 122, 123, 124, 126, 145, 146 and from the shift switch 47, and then controls the vehicle 10 according to the received signals. The processor 110p of the main control unit 110 controls the vehicle 10 by outputting instructions to the drive device control unit 300, the lean motor control unit 400, and the steering motor control unit 500 (described in detail later).
The processor 300p of the drive device control unit 300 controls the electric motors 51L, 51R according to the instruction from the main control unit 110. The processor 400p of the lean motor control unit 400 controls the lean motor 25 according to the instruction from the main control unit 110. The processor 500p of the steering motor control unit 500 controls the steering motor 65 according to the instruction from the main control unit 110. These control units 300, 400, 500 respectively have electric power control modules 300c, 400c, 500c which supply the motors 51L, 51R, 25, 65 under control with electric power from the battery 120. The electric power control modules 300c, 400c, 500c are configured using an electric circuit (e.g. inverter circuit).
Hereinafter, a phrase “a processor 110p, 300p, 400p, 500p of a control unit 110, 300, 400, 500 performs a process” is sometimes expressed briefly as a phrase “a control unit 110, 300, 400, 500 performs a process.”
The lock motor control unit 600 includes an electric circuit (e.g. inverter circuit) which supplies the lock motor 925 of the lock device 900 with electric power from the battery 120.
In S100, the main control unit 110 acquires signals from the sensors 122, 123, 124, 126, 145, 146 and from the shift switch 47. Then, the main control unit 110 determines the velocity V, steering wheel angle, wheel angle AF, vertically downward direction DD, accelerator operation amount, brake operation amount, and driving mode.
In S110, the main control unit 110 determines whether or not a condition is met that ‘the driving mode is either “drive” or “neutral.” The condition in S110 indicates that the vehicle 10 is moving forward. If the determination result in S110 is “Yes,” the main control unit 110 proceeds to S130.
In S130, the controller 100 controls the lean motor 25 and the steering motor 65 so that the vehicle 10 moves in the direction mapped to the steering wheel angle. The outline of S130 is as follows. The main control unit 110 uses the steering wheel angle and the vehicle velocity V to determine a first target lean angle T1. The first target lean angle T1 represents a target value of the lean angle T. As described later, the absolute value of the first target lean angle T1 is increased with an increase in the absolute value of the steering wheel angle. When the vehicle body 90 is caused to rotate in its width direction so that the lean angle T approaches the first target lean angle T1, the rotational direction of the vehicle body 90 is referred to as target direction. The target direction is either right direction or left direction. The lean motor control unit 400 causes the lean motor 25 to output a lean torque in the target direction so that the lean angle T approaches the first target lean angle T1. In addition, the steering motor control unit 500 can cause the steering motor 65 to output a torque for turning the front wheel 12F in a direction opposite to the target direction. Accordingly, the vehicle 10 properly moves toward the direction corresponding to the steering wheel angle. The process of S130 will be discussed in detail later.
If the driving mode is not “drive” or “neutral” (i.e. if the driving mode is either “reverse” or “parking”), the determination result in S110 is “No.” Accordingly, the main control unit 110 proceeds to S170.
In S170, the main control unit 110 determines the first target lean angle T1 in a similar manner to S130. The main control unit 110 supplies the lean motor control unit 400 with an instruction for controlling the lean motor 25 so that the lean angle T is equal to the first target lean angle T1. According to the instruction, the lean motor control unit 400 activates the lean motor 25 so that the lean angle T is equal to the first target lean angle T1. The lean motor control unit 400 performs a feedback control of the lean motor 25 which uses a difference between the lean angle T and the first target lean angle T1 (e.g. a so-called PID (Proportional Integral Derivative) control).
Also, the main control unit 110 uses the steering wheel angle and the vehicle velocity V to determine a first target wheel angle AFt1. Information which represents the correspondence relationship between the first target wheel angle AFt1 and the steering wheel angle and vehicle velocity V is predefined by the map data MAF stored in the non-volatile memory 110n of the main control unit 110 (
In this embodiment, the correspondence relationship between the steering wheel angle and vehicle velocity V and the first target wheel angle AFt1 is the same as that between the first target lean angle T1 and vehicle velocity V and the wheel angle AF determined using the above Equations 6, 7. Accordingly, the same first target wheel angle AFt1 can be determined using the first target lean angle T1 and the vehicle velocity V. For example, the map data MAF may define the correspondence relationship between the combination of first target lean angle T1 and vehicle velocity V and the first target wheel angle AFt1. Then, the main control unit 110 may use the first target lean angle T1 and the vehicle velocity V to determine the first target wheel angle AFt1.
The main control unit 110 supplies the steering motor control unit 500 with an instruction for controlling the steering motor 65 so that the wheel angle AF is equal to the first target wheel angle AFt1. According to the instruction, the steering motor control unit 500 activates the steering motor 65 so that the wheel angle AF is equal to the first target wheel angle AFt1. The steering motor control unit 500 performs a feedback control of the steering motor 65 which uses a difference between the wheel angle AF and the first target wheel angle AFt1 (e.g. a so-called PID (Proportional Integral Derivative) control).
Accordingly, the vehicle 10 properly moves toward the direction corresponding to the steering wheel angle.
In response to S130 or S170 being performed, the process of
The main control unit 110 (
The main control unit 110 supplies the drive device control unit 300 with an instruction for decreasing output power of the electric motors 51L, 51R when the brake operation amount becomes larger than zero. According to the instruction, the drive device control unit 300 controls the electric motors 51L, 51R so as to decrease their output power. It should be noted that the vehicle 10 preferably has a brake device which frictionally reduces rotational rate of at least one of all the wheels 12F, 12L, 12R. In addition, the brake device preferably reduces the rotational rate of the at least one wheel when the user steps on the brake pedal 46.
A3. Control Process:
The control process of S130 (
The processing modules 112, 114, 116, 212, 214, 216, 218 of the main control unit 110 are implemented by the processor 110p of the main control unit 110 (
In S210, the lean angle specifying module 112 (
In S220, the target lean angle determination module 114 (
In S230, the summing point 116 (
In S232, the first determination module 212 (
In S234, the first derivative calculation module 214 (
In S236, the second determination module 216 (
In S238, the second derivative calculation module 218 (
S240-S280 are performed by the steering motor control unit 500. S300-S340 are performed by the lean motor control unit 400.
In this situation, the lean motor control unit 400 causes the lean motor 25 (
The steering motor control unit 500 causes the steering motor 65 to output a turning torque TqT (
As shown in
In addition, a portion on the downward direction DD side of the vehicle 10 which includes the front wheel 12F (in particular, a portion on the downward direction DD side of the gravity center 90c) moves toward the left direction DL side as indicated by the arrow AL in
In addition, the vehicle body 90 can use precession movement of the front wheel 12F to rotate to the target direction DTg.
As described above, the counter torque TqT can use the centrifugal force F3 (
In this embodiment, when the magnitude of the lean angle difference dT is larger, the larger counter torque TqT facilitates the change in the lean angle T of the vehicle body 90. When the magnitude of the lean angle difference dT is smaller, the smaller turning torque allows the front wheel 12F to turn naturally. S240-S280 and S300-S340 of
In S240, S250, S260, the steering motor control unit 500 determines control values Vc1, Vc2, Vc3 that are used to control the turning torque.
In S240 (
In S730 (
In S750 (
In S760, the first D control module 516 uses the lean angle difference dT and a first D gain Kd1 to determine a first derivative term Vd1. In this embodiment, the first D gain Kd1 is predetermined. The first derivative term Vd1 may be determined by a well-known method for determining a derivative term of PID control. For example, a value obtained by multiplying a derivative value of the lean angle difference dT by the first D gain Kd1 is output as the first derivative term Vd1. The derivative value of the lean angle difference dT may be calculated by a variety of methods. For example, a value obtained by subtracting a lean angle difference dT at a point of time in the past by a particular time difference from current time from a current lean angle difference dT may be employed as derivative value. The time difference for determining the derivative value of the lean angle difference dT may be predetermined, or may be determined based on another parameter (e.g. the vehicle velocity V) instead. It should be noted that the first D gain Kd1 may be a variable value that varies depending on another parameter (e.g. the vehicle velocity V).
It should be noted that S730, S750 for determining the first proportional term Vp1, and S760 for determining the first derivative term Vd1 are performed in parallel.
In S770, the first summing point 518 (
In S250 (
In S820 (
If the absolute value of the lean angle difference dT has not increased (FL1=1, S820: No), that is, the absolute value of the lean angle difference dT remains unchanged or has decreased, then in S840 the second P gain control module 522 uses the vehicle velocity V to determine the second P gain Kp2 according to a second correspondence relationship R22. The second correspondence relationship R22 is one between the vehicle velocity V and the second P gain Kp2. The second correspondence relationship R22 is predefined by the map data Mp22 stored in the non-volatile memory 500n of the steering motor control unit 500 (
On the graph of
In S850, the second P control module 524 (
In S860, the second D control module 526 uses the angular velocity Vt and a second D gain Kd2 to determine a second derivative term Vd2. In this embodiment, the second D gain Kd2 is predetermined. The second derivative term Vd2 may be determined by a well-known method for determining a derivative term of PID control. For example, a value obtained by multiplying a derivative value of the angular velocity Vt by the second D gain Kd2 is output as the second derivative term Vd2. The time difference for determining the derivative value of the angular velocity Vt may be predetermined, or may be determined based on another parameter (e.g. the vehicle velocity V) instead. It should be noted that the second D gain Kd2 may be a variable value that varies depending on another parameter (e.g. the vehicle velocity V).
It should be noted that S820-S850 for determining the second proportional term Vp2 and S860 for determining the second derivative term Vd2 are performed in parallel.
In S870, the second summing point 528 (
In S260 (
In S910 (
If the absolute value of the angular velocity Vt has increased (FL2=0, S910: Yes), then in S920 the third P gain control module 532 (
If the absolute value of the lean angle difference dT has not increased (FL1=1, S920: No), that is, the absolute value of the lean angle difference dT remains unchanged or has decreased, then in S940 the third P gain control module 532 uses the vehicle velocity V to determine the third P gain Kp3 according to a second correspondence relationship R32. The second correspondence relationship R32 is one between the vehicle velocity V and the third P gain Kp3. The second correspondence relationship R32 is predefined by the map data Mp32 stored in the non-volatile memory 500n of the steering motor control unit 500 (
On the graph of
In S950, the third P control module 534 (
In S960, the third D control module 536 uses the angular acceleration At and the third D gain Kd3 to determine the third derivative term Vd3. In this embodiment, the third D gain Kd3 is predetermined. The third derivative term Vd3 may be determined by a well-known method for determining a derivative term of PID control. For example, a value obtained by multiplying a derivative value of the angular acceleration At by the third D gain Kd3 is output as the third derivative term Vd3. The time difference for determining the derivative value of the angular acceleration At may be predetermined, or may be determined based on another parameter (e.g. the vehicle velocity V) instead. It should be noted that the third D gain Kd3 may be a variable value that varies depending on another parameter (e.g. the vehicle velocity V).
It should be noted that S920-S950 for determining the third proportional term Vp3 and S960 for determining the third derivative term Vd3 are performed in parallel.
In S970, the third summing point 538 (
It should be noted that S240, S250, S260 of
In S270 (
The turning actuation control value Vca indicates a target value of turning torque of the steering motor 65. Hereinafter, the torque indicated by the turning actuation control value Vca may be referred to as target turning torque TqTt. The turning actuation control value Vca indicates, for example, magnitude and direction of electric current to be supplied to the steering motor 65. The magnitude of electric power (i.e. the magnitude of torque of the steering motor 65) is increased with an increase in the absolute value of the control value Vca. In S270, the steering motor control unit 500 (more specifically, the fourth summing point 590) may be considered to determine the target turning torque TqTt of the steering motor 65. In S280, the steering motor control unit 500 (more specifically, the electric power control module 500c) may be considered to control the torque of the steering motor 65 to become the target turning torque TqTt.
Each control value Vc1, Vc2, Vc3, and thus each term Vp1, Vd1, Vp2, Vd2, Vp3, Vd3 constitutes a part of the turning actuation control value Vca. Therefore, each control value Vc1, Vc2, Vc3, and thus each term Vp1, Vd1, Vp2, Vd2, Vp3, Vd3 may be also considered to be a kind of control value that represents the turning torque of the steering motor 65.
The first control value Vc1 is determined through a feedback control using the lean angle difference dT. The direction of the turning torque indicated by the first control value Vc1 is opposite to the target direction DTg as described with reference to
The second control value Vc2 and the third control value Vc3 represent the turning torque for suppressing unintended change in the lean angle T due to a disturbance (e.g. irregularities of road) or overshoot. When the lean angle T changes rapidly due to a disturbance etc., the respective magnitudes of the second control value Vc2 and third control value Vc3 become larger. With the vehicle 10 traveling stably, the angular velocity Vt and the angular acceleration At are smaller, and therefore the respective magnitudes of the second control value Vc2 and third control value Vc3 are also smaller.
The user usually operates the steering wheel 41a moderately. In this case, the magnitudes of the angular velocity Vt and angular acceleration At of the lean angle T do not increase as significantly as that of the lean angle difference dT does. Accordingly, the magnitude of the first control value Vc1 determined by the feedback control of the lean angle difference dT is larger than those of the control values Vc2, Vc3 determined by the feedback control of the angular velocity Vt and angular acceleration At of the lean angle T. That is, the major component of the target turning torque TqTt of the steering motor 65 can be represented by the first control value Vc1. In addition, the first P gain Kp1 and the first D gain Kd1 are determined so that the magnitude of the first proportional term Vp1 is larger than that of the first derivative term Vd1 when the user operates the steering wheel 41a moderately. That is, the major component of the target turning torque TqTt of the steering motor 65 can be represented by the first proportional term Vp1. The turning torque is controlled according to such a target turning torque TqTt, and therefore it is possible to readily cause the lean angle T to approach the first target lean angle T1 as described with reference to
The first control value Vc1 is determined using the lean angle difference dT. Therefore, the first control value Vc1 is determined to be a value appropriate for the lean angle difference dT. Accordingly, the driving stability of the vehicle 10 can be improved.
In addition, the magnitude of the first control value Vc1 (in this case, that of the first proportional term Vp1), i.e. that of the target turning torque TqTt may be increased with an increase in the magnitude of the lean angle difference dT. As in
When the lean angle T approaches the first target lean angle T1, and thus the magnitude of the lean angle difference dT decreases as in
In this embodiment, the first P gain Kp1 and the first D gain Kd1 are determined so that the first P gain Kp 1 is approximately equal to an angle difference-torque ratio, which is a ratio of the magnitude of the turning torque represented by the first control value Vc1 to the magnitude of the lean angle difference dT (e.g. the first D gain Kd1 is sufficiently small). And, the first P gain Kp1 changes according to the vehicle velocity V, as shown in
In addition, as shown in
The second control value Vc2 is determined through a feedback control using the angular velocity Vt of the lean angle T. The direction of the turning torque indicated by the second control value Vc2 is the same as the direction of change in the lean angle T. For example, when the vehicle upward direction DVU of the vehicle body 90 turns to the left direction due to a disturbance etc., the lean angle T changes toward the left direction. In this case, the direction of the turning torque indicated by the second control value Vc2 is the left direction. This turning torque causes the front wheel 12F to turn to the left direction. The front wheel 12F turns to the left direction, and thereby the vehicle 10 turns to the left direction. Accordingly, a rightward centrifugal force acts on the vehicle body 90. As a result, the vehicle upward direction DVU of the vehicle body 90 is suppressed from turning to the left direction side unintentionally.
In this embodiment, the second P gain Kp2 and the second D gain Kd2 are determined so that the second P gain Kp2 is approximately equal to an angular velocity-torque ratio, which is a ratio of the magnitude of the turning torque represented by the second control value Vc2 to the magnitude of the angular velocity Vt (e.g. the second D gain Kd2 is sufficiently small). And, the second P gain Kp2 changes according to the vehicle velocity V, as shown in
In addition, as shown in
In addition, as described with reference to S820-S840 of
The third control value Vc3 is determined through a feedback control using the angular acceleration At of the lean angle T. The direction of the turning torque indicated by the third control value Vc3 is the same as the direction of change in the angular velocity Vt of the lean angle T. When the vehicle upward direction DVU of the vehicle body 90 begins to turn to the left direction due to a disturbance etc., the lean angle T begins to change toward the left direction. Accordingly, the angular velocity Vt increases toward the left direction (that is, the angular velocity Vt changes toward the left direction). In this case, the direction of the turning torque indicated by the third control value Vc3 is the left direction. This turning torque causes the front wheel 12F to turn to the left direction. The front wheel 12F turns to the left direction, and thereby the vehicle 10 turns to the left direction. Accordingly, a rightward centrifugal force acts on the vehicle body 90. As a result, the vehicle upward direction DVU of the vehicle body 90 is suppressed from turning to the left direction side unintentionally. It should be note that in a state of the vehicle upward direction DVU of the vehicle body 90 turning to the left direction, the direction of change of the angular velocity Vt is the right direction when the magnitude of the angular velocity Vt has decreased.
In this embodiment, the third P gain Kp3 and the third D gain Kd3 are determined so that the third P gain Kp3 is approximately equal to an angular acceleration-torque ratio, which is a ratio of the magnitude of the turning torque represented by the third control value Vc3 to the magnitude of the angular acceleration At (e.g. the third D gain Kd3 is sufficiently small). And, the third P gain Kp3 changes according to the vehicle velocity V, as shown in
In addition, as shown in
In addition, as described with reference to S920, S980 of
In addition, as described with reference to S920-S940 of
Furthermore, the vehicle 10 includes the lean motor 25 (
In S310 (
In S320, the D control module 416 uses the lean angle difference dT and the D gain Kdb to determine a derivative term Vdb. In this embodiment, the D gain Kdb is predetermined. The derivative term Vdb may be determined by a well-known method for determining a derivative term of PID control. For example, a value obtained by multiplying a derivative value of the lean angle difference dT by the D gain Kdb is output as the derivative term Vdb. The time difference for determining the derivative value of the lean angle difference dT may be predetermined, or may be determined based on another parameter (e.g. the vehicle velocity V) instead. It should be noted that the D gain Kdb may be a variable value that varies depending on another parameter (e.g. the vehicle velocity V).
It should be noted that S310 for determining the proportional term Vpb and S320 for determining the derivative term Vdb are performed in parallel.
In S330, the summing point 490 (
The lean actuation control value Vcb indicates a target value of lean torque of the lean motor 25. Hereinafter, the torque indicated by the lean actuation control value Vcb may be referred to as target lean torque. The direction of the lean torque indicated by the lean actuation control value Vcb is the same as the target direction DTg, i.e. the rotational direction of the vehicle body 90 for causing the lean angle T to approach the first target lean angle T1, as described with reference to
It should be noted that S240-S280 for controlling the steering motor 65 and S310-S340 for controlling the lean motor 25 are performed in parallel. Then, the process of
It should be noted that the lock motor 925 (
If the determination result in S110 is “Yes,” then in S120, the main control unit 110 (
If the magnitude of the vehicle velocity V is equal to or larger than the threshold value Vth (S120: Yes), then in S125, the main control unit 110 causes the lock device 900 to unlock the lean device 89. In this embodiment, the main control unit 110 causes the lock motor control unit 600 to drive the lock motor 925 so that the state of the lock device 900 becomes the unlock state. If the state of the lock device 900 is already the unlock state, then the main control unit 110 maintains the unlock state of the lock device 900 without driving the lock motor 925.
The process of S130 is the same as that of S130 in
If the magnitude of the vehicle velocity V is smaller than the threshold value Vth (S120: No), then in S145, the main control unit 110 causes the lock device 900 to lock the lean device 89. In this embodiment, the main control unit 110 causes the lock motor control unit 600 to drive the lock motor 925 so that the state of the lock device 900 becomes the lock state. If the state of the lock device 900 is already the lock state, then the main control unit 110 maintains the lock state of the lock device 900 without driving the lock motor 925. As such, the control angle Tc and thus the lean angle T are fixed.
In S150, the controller 100 performs a third control for controlling the steering motor 65 so that the vehicle 10 moves in the direction mapped to the steering wheel angle.
In S710, the main control unit 110 uses the steering wheel angle Ai and the vehicle velocity V to determine a target wheel angle. The target wheel angle is determined in the same manner as the target wheel angle in S170 of
In S720, the main control unit 110 supplies the steering motor control unit 500 with an instruction for controlling the steering motor 65 so that the wheel angle AF becomes equal to the target wheel angle. According to the instruction, the steering motor control unit 500 drives the steering motor 65 so that the wheel angle AF becomes equal to the target wheel angle. The steering motor control unit 500 performs a feedback control of the steering motor 65 which uses a difference between the wheel angle AF and the target wheel angle (e.g. a so-called PID (Proportional Integral Derivative) control). In S720, the steering motor control unit 500 causes the steering motor 65 to output a torque (sometimes referred to as forward torque) that turns the front fork 17 (and thus the front wheel 12F) toward the target direction DTg, instead of the counter torque (
In this manner, if the magnitude of the vehicle velocity V is smaller than the threshold value Vth, then the lock device 900 locks the lean device 89. As such, the control angle Tc (and thus the lean angle T) are fixed. Accordingly, the lean angle T is suppressed from becoming unstable. In addition, if the magnitude of the vehicle velocity V is smaller than the threshold value Vth, then the turning torque of the steering motor 65 turns the front wheel 12F toward the target direction DTg so that the wheel angle AF becomes equal to the target wheel angle. Accordingly, the vehicle 10 can move toward the direction indicated by the steering wheel angle Ai.
Then, the controller completes the process of
In response to any of S130, S150, S170 being performed, the process of
If the moving vehicle 10 decelerates, and then the vehicle velocity V changes from a value larger than or equal to the threshold value Vth to a value smaller than the threshold value Vth, then the state of the lock device 900 switches from the unlock state to the lock state. In a phase where the vehicle velocity V is equal to or larger than the threshold value Vth, the vehicle 10 can use the counter torque to travel stably in the direction indicated by the steering wheel angle Ai, as described with reference to
It should be noted that the control angle Tc when the lean device 89 is locked is the same as the control angle Tc immediately before locking the lean device 89. The vehicle 10 is usually decelerated with the magnitude of the steering wheel angle Ai smaller. Therefore, the step of locking the lean device 89 due to a deceleration of the vehicle 10 (
If the vehicle 10 accelerates, and then the vehicle velocity V changes from a value smaller than the threshold value Vth to a value larger than or equal to the threshold value Vth, then the state of the lock device 900 switches from the lock state to the unlock state. In a phase where the vehicle velocity V is smaller than the threshold value Vth, the lean device 89 is locked by the lock device 900, and therefore the lean angle T of the vehicle 10 is suppressed from becoming unstable. In addition, the steering motor 65 turns the front wheel 12F so that the wheel angle AF becomes equal to the target wheel angle. Accordingly, the vehicle 10 can move stably toward the direction indicated by the steering wheel angle Ai. If the vehicle velocity V becomes equal to or larger than the threshold value Vth, then the lean device 89 is unlocked. Then, the vehicle 10 can use the counter torque to travel stably in the direction indicated by the steering wheel angle Ai, as described with reference to
The vehicle 10 is usually accelerated with the magnitude of the steering wheel angle Ai smaller. Therefore, when the lean device 89 is unlocked due to an acceleration of the vehicle 10 (
B. Modifications:
(1) As the process of controlling the turning torque, a variety of other processes may be employed instead of the processes described above with reference to
In addition, in the graph of
In addition, in the graph of
In
In general, the controller 100 may use one or more control values, including a control value indicative of a counter torque (e.g. the first proportional term Vp1), to determine the turning actuation control value Vca (and thus the target turning torque). Where the controller 100 may calculate a sum of the one or more control values as the turning actuation control value Vca.
(2) The controller 100 may be configured in a variety of ways to perform processes for controlling the device outputting the turning torque (e.g. the steering motor 65) and the device outputting the lean torque (e.g. the lean motor 25). For example, the controller 100 may be configured by using a single computer. At least part of the controller 100 may be configured with dedicated hardware such as ASIC (Application Specific Integrated Circuit). For example, the lean motor control unit 400 and the steering motor control unit 500 in
Alternatively, as the lean angle used for control of each of the turning torque and the lean torque, a variety of angles that indicates a degree of lean of the vehicle body 90 in its width direction may be employed instead of the lean angle T (
(3) The front wheel 12F (
In general, the turn wheel support unit may include K (K is an integer equal to or larger than 1) supporting members. And, each supporting member may support one or more turn wheels. The turn wheel support unit may include K turning devices. The K turning devices may support turnably the K supporting members, respectively. The turn wheel support unit may include K turning actuators. The K turning actuators and the K supporting members have one-to-one correspondence. And, each turning actuator may be configured to apply the turning torque to the corresponding single supporting member. Alternatively, the turn wheel support unit may include a single turning actuator. The single turning actuator may be configured to apply the turning torque to each of the K supporting members.
In either case, the turn wheel support unit is preferably configured to allow one or more turn wheel to turn to right and left relative to the vehicle body following a change in lean of the vehicle body independently of operation amount input to the operation input unit (e.g. the steering wheel 41a). For example, a turning device secured to the vehicle body preferably supports turnably the supporting member. In this case, the supporting member also leans along with the vehicle body when the vehicle body leans. Accordingly, as described above with regard to
(4) The operation input unit may be a variety of other devices configured to be handled to input operation amount indicative of a turning direction and a degree of turn, instead of the device rotatable to right and left such as the steering wheel 41a (
(5) The lean device may be configured in any other way to lean the vehicle body 90 in its width direction instead of the configuration of the lean device 89 in
In general, the lean device may include a “first member which is connected directly or indirectly to at least one of a pair of wheels spaced apart from each other in the width direction of the vehicle,” a “second member connected directly or indirectly to the vehicle body,” and an actuator. The actuator applies to the first member and the second member a force that changes the relative position between the first member and the second member (e.g., a torque that changes the orientation of the second member relative to the first member). The lean device may further include a “connection device for movably connecting the first member to the second member.” The connection device may be a hydraulic cylinder that slidably connects the first member to the second member. Alternatively, the connection device may be a bearing that rotatably connects the first member to the second member. The bearing may be a ball bearing, or may be a sliding bearing instead. The actuator may be an electric motor such as the lean motor 25. Alternatively, the actuator may be a pump if the lean device includes the hydraulic cylinder.
(6) The connection which is connected to the operation input unit and to the supporting member of the turn wheel support unit may be configured in a variety of other ways instead of the configuration of the connection 50 of
(7) A variety of configurations may be employed as the total number and arrangement of the plurality of wheels. For example, there may be one front wheel in total and one rear wheel in total. There may be two front wheels in total and one rear wheel in total. There may be two front wheels in total and two rear wheels in total. A pair of wheels spaced apart from each other in the width direction may be front wheels, and may also be turn wheels. The rear wheels may be turn wheels. The drive wheel may be the front wheel.
In general, the vehicle includes N (N is an integer equal to or larger than 2) wheels including at least one front wheel and at least one rear wheel. And, the N wheels include at least one turn wheel turnable to right and left. If the total number of wheels N is equal to 2, the lean device such as the lean device 89 is omitted. The vehicle may include N wheels, including a pair of wheels spaced apart from each other in the width direction of the vehicle, and at least one other wheel. In this case, the total number of wheels N is equal to or larger than 3. The pair of wheels may be front wheels, or may be rear wheels instead. In this case, at least one of the pair of wheels or the other wheel(s) are preferably configured as one or more turn wheels turnable to right and left relative to the forward movement direction of the vehicle. That is, only the pair of wheels may be turn wheels, only the other wheel(s) may be turn wheel(s), or the three or more wheels including the pair of wheels and the other wheel(s) may be tun wheels. In this case, the total number of the other wheel(s) included in the one or more turn wheels may be any number. The controls in
(8) The lean actuator may be any device configured to apply the lean torque to the vehicle body. For example, the lean actuator may include a weight connected to the vehicle body so that it can slide relative to the vehicle body in its width direction, and an electric motor for controlling the position of the weight relative to the vehicle body. When the weight moves to the right side of the vehicle body, the vehicle body can lean to right direction side, and when the weight moves to the left side of the vehicle body, the vehicle body can lean to left direction side. However, such a lean actuator may be omitted.
(9) The lock device may be any device configured to lock the lean device instead of the lock device 900 in
(10) The method of controlling the vehicle may be a variety of other methods instead of the method described above with reference to
(11) The controller 100 (e.g. the main control unit 110) may determine the first target lean angle T1 using the steering wheel angle Ai without using the vehicle velocity V. In general, the controller 100 may determine the target lean angle using one or more parameters including the steering wheel angle Ai (more generally, the operation amount input to the operation input unit). Without limiting to the vehicle velocity V, it is possible to employ a variety of other parameters as parameter other than the operation amount.
The controller 100 uses a yaw rate of the vehicle 10 in addition to the steering wheel angle Ai to determine the first target lean angle T1. The yaw rate of the vehicle 10, which is change rate of yaw angle, is angular velocity of rotation about an axis that passes through the gravity center of the vehicle 10 and is parallel to the vertically upward direction DU. The current yaw rate can be determined using information from the gyroscope sensor 126g. The vehicle 10 can be subject to external factors such as wind. The traveling direction of the vehicle 10 can be affected by such a force. For example, assume that the steering wheel angle Ai is equal to zero, and the vehicle 10 is moving straight ahead on a horizontal road. If the wind blows from right to left, the vehicle body 90 is subject to a force in the left direction DL. As a result, the vehicle body 90 can lean to the left direction DL side, and thus the vehicle 10 can turn to the left direction DL. In order to suppress such an unintended turn, the controller 100 (e.g. the main control unit 110) may use the steering wheel angle Ai and the current yaw rate to determine the target lean angle. The controller 100 uses the steering wheel angle Ai to identify a target yaw rate. The correspondence relationship between the steering wheel angle Ai and the target yaw rate is predetermined. For example, the target yaw rate of zero is mapped to the steering wheel angle Ai of zero. The target yaw rate indicative of right turn is mapped to the steering wheel angle Ai indicative of right turn. The controller 100 references this correspondence relationship to identify the target yaw rate corresponding to the steering wheel angle Ai. Then, the main control unit 110 uses a difference between the target yaw rate and the current yaw rate to determine the target lean angle. For example, the controller 100 calculates the target lean angle by adding to the current lean angle T a correction value corresponding to the yaw rate difference between the target yaw rate and the current yaw rate. The correspondence relationship between the yaw rate difference and the correction value may be determined experimentally in advance. For example, if the current yaw rate is equal to the target yaw rate (yaw rate difference=0), the correction value is equal to zero. In this case, the first target lean angle T1 is equal to the current lean angle T. If the target yaw rate is equal to zero (i.e. Straight movement), and the current yaw rate indicates left turn, the correction value corrects the first target lean angle T1 to an angle rotated to the right direction DR side relative to the current lean angle T. For example, if the vehicle 10 turns to left unintentionally due to right-to-left wind in spite of the steering wheel angle Ai equal to zero, the first target lean angle T1 is determined to be an angle that indicates that the vehicle body 90 leans to the right direction DR side. This enables the vehicle 10 to resist the wind to move straight ahead. In this manner, deviation of the vehicle 10 from its intended traveling direction due to external factors is suppressed.
(12) The control unit 126c of the vertical direction sensor 126 may use other information related to the movement of the vehicle 10 in addition to the information from the gyroscope sensor 126g and the acceleration sensor 126a to detect the vertically downward direction DD. As the other information, for example, the location of the vehicle 10 determined by using GPS (Global Positioning System) may be used. The control unit 126c may correct the vertically downward direction DD according to change in location determined by GPS. An amount of correction based on change in location determined by GPS may be determined experimentally in advance. It should be noted that the control unit 126c may be a variety of electric circuits, for example, an electric circuit with a computer or an electric circuit (e.g. ASIC) without a computer. The gyroscope sensor 126g may be a sensor that detects an angular velocity instead of angular acceleration.
(13) The vehicle may be configured in a variety of other ways instead of the respective configuration of the above embodiments and modifications. For example, in the embodiment in
In each embodiment described above, some of the components which are achieved by hardware may be substituted with software while some or all of the components which are achieved by software may be substituted with hardware. For example, the function of the controller 100 in
In addition, if some or all of the functions of the present invention are achieved by a computer program, the program can be provided in the form of a computer-readable storage medium (e.g. non-transitory storage medium) having the program stored therein. The program can be used while being stored in a storage medium (computer-readable storage medium) which is the same as or different from the provided storage medium. The “computer-readable storage medium” is not limited to a portable storage medium such as memory card or CD-ROM, but may also include an internal storage within the computer such as various types of ROM, and an external storage connected to the computer such as hard disk drive.
The present invention has been described above with reference to the embodiments and the modifications although the above-described embodiments are intended to facilitate the understanding of the invention, but not to limit the invention. The present invention may be modified or improved without departing from the spirit of the invention, and includes its equivalents.
INDUSTRIAL APPLICABILITYThe present invention can be preferably used for a vehicle.
DESCRIPTION OF THE REFERENCES
- 10 vehicle
- 11 seat
- 12F front wheel
- 12L left rear wheel
- 12R right rear wheel
- 12Fc gravity center
- 12La wheel
- 12Lb tire
- 12Ra wheel
- 12Rb tire
- 17 front fork
- 20 main body
- 20a front portion
- 20b bottom portion
- 20c rear portion
- 20d support portion
- 21 center longitudinal link member
- 25 lean motor
- 30 link mechanism
- 31D lower lateral link member
- 31U upper lateral link member
- 33L left longitudinal link member
- 33R right longitudinal link member
- 38 bearing
- 39 bearing
- 41 front wheel support device
- 41a steering wheel
- 41ax supporting rod
- 45 accelerator pedal
- 46 brake pedal
- 47 shift switch
- 50 connection
- 51 first portion
- 52 second portion
- 53 third portion
- 51L left electric motor
- 51R right electric motor
- 65 steering motor
- 68 bearing
- 70 suspension system
- 70L left suspension
- 70R right suspension
- 71L, 71R coil spring
- 72L, 72R shock absorber
- 75 connector rod
- 80 rear wheel support
- 82 first support portion
- 83 second support portion
- 89 lean device
- 90 vehicle body
- 90c gravity center
- 100 controller
- 110 main control unit
- 110g, 300g, 400g, 500g program
- 110n, 300n, 400n, 500n non-volatile memory
- 110p, 300p, 400p, 500p processor
- 110v, 300v, 400v, 500v volatile memory
- 120 battery
- 122 vehicle velocity sensor
- 123 steering wheel angle sensor
- 124 wheel angle sensor
- 126 vertical direction sensor
- 126a acceleration sensor
- 126c control unit
- 126g gyroscope sensor
- 127 lean angle sensor
- 145 accelerator pedal sensor
- 146 brake pedal sensor
- 300 drive device control unit
- 300c electric power control module
- 400 lean motor control unit
- 400c electric power control module
- 500 steering motor control unit
- 500c electric power control module
- 600 lock motor control unit
- 900 lock device
- 910 brake rotor
- 920 brake caliper
- 930 brake pad
- 925 lock motor
Claims
1. A vehicle comprising:
- a vehicle body;
- N (N is an integer equal to or larger than 2) wheels including one or more turn wheels turnable to right and left relative to a forward movement direction of the vehicle, the N wheels including at least one front wheel and at least one rear wheel;
- a lean angle sensor configured to measure a lean angle in a width direction of the vehicle body;
- an operation input unit configured to be handled to input an operation amount indicative of a turning direction and a degree of turn;
- a turn wheel support unit that supports the one or more turn wheels, and
- a controller,
- wherein the turn wheel support unit comprises: a supporting member that rotatably supports the one or more turn wheels; a turning device that supports the supporting member turnably to right and left relative to the vehicle body; and a turning actuator configured to apply to the supporting member a turning torque for turning the supporting member, and
- wherein a lean angle targeted by the vehicle body is referred to as a target lean angle;
- a difference between the target lean angle and the lean angle of the vehicle body is referred to as a lean angle difference; and
- a target torque of the turning actuator is referred to as a target turning torque,
- wherein the controller is configured to: determine the target lean angle by using one or more parameters including the operation amount; determine a first type control value indicative of a first torque by using the lean angle difference, the first torque causing the supporting member to turn in a direction opposite to a target direction that is a rotational direction to rotate the vehicle body in its width direction so that the lean angle approaches the target lean angle, the target direction being either a right direction or a left direction; determine the target turning torque by using one or more control values including the first type control value; and control the turning actuator according to the target turning torque.
2. The vehicle of claim 1,
- wherein a ratio of a magnitude of the first torque indicated by the first type control value to a magnitude of the lean angle difference is referred to as an angle difference-torque ratio, and
- wherein the controller is configured to determine the first type control value so that the angle difference-torque ratio changes according to a vehicle velocity.
3. The vehicle of claim 2,
- wherein the controller is configured to determine the first type control value so that the angle difference-torque ratio when a magnitude of the vehicle velocity is smaller than a first threshold value is larger than the angle difference-torque ratio when the magnitude of the vehicle velocity is larger than the first threshold value.
4. The vehicle of claim 1,
- wherein the controller is configured to: determine a second type control value indicative of a second torque by using an angular velocity of the lean angle of the vehicle body, the second torque causing the supporting member to turn in a direction of change in the lean angle out of the right direction and the left direction; and determine the target turning torque by using two or more control values including the first type control value and the second type control value.
5. The vehicle of claim 4,
- wherein a ratio of a magnitude of the second torque indicated by the second type control value to a magnitude of the angular velocity of the lean angle is referred to as an angular velocity-torque ratio, and
- wherein the controller is configured to determine the second type control value so that the angular velocity-torque ratio changes according to the vehicle velocity.
6. The vehicle of claim 5,
- wherein the controller is configured to determine the second type control value so that the angular velocity-torque ratio when a magnitude of the vehicle velocity is smaller than a second threshold value is larger than the angular velocity-torque ratio when a magnitude of the vehicle velocity is larger than the second threshold value.
7. The vehicle of claim 1,
- wherein the controller is configured to: determine a third type control value indicative of a third torque by using an angular acceleration of the lean angle of the vehicle body, the third torque causing the supporting member to turn in a direction of change in angular velocity of the lean angle out of the right direction and the left direction; and determine the target turning torque by using two or more control values including the first type control value and the third type control value.
8. The vehicle of claim 7,
- wherein a ratio of a magnitude of the third torque indicated by the third type control value to a magnitude of the angular acceleration of the lean angle is referred to as an angular acceleration-torque ratio, and
- wherein the controller is configured to determine the third type control value so that the angular acceleration-torque ratio changes according to a vehicle velocity.
9. The vehicle of claim 8,
- wherein the controller is configured to determine the third type control value so that the angular acceleration-torque ratio when a magnitude of the vehicle velocity is smaller than a third threshold value is larger than the angular acceleration-torque ratio when a magnitude of the vehicle velocity is larger than the third threshold value.
10. The vehicle of claim 1, comprising:
- a lean actuator configured to apply to the vehicle body a lean torque for controlling the lean angle of the vehicle body.
11. The vehicle of claim 1,
- wherein the N wheels include three or more wheels including a pair of wheels spaced apart from each other in the width direction;
- wherein the vehicle comprises: a lean device configured to lean the vehicle body in the width direction; and a lock device configured to lock the lean device, and
- wherein the controller is configured to: if a magnitude of the vehicle velocity is equal to or larger than a fourth threshold value, cause the lock device to unlock the lean device, and control the turning actuator according to the target turning torque, and if a magnitude of the vehicle velocity is smaller than the fourth threshold value, cause the lock device to lock the lean device, and cause the turning actuator to output the turning torque that causes the supporting member to turn in the target direction.
Type: Application
Filed: Jul 25, 2019
Publication Date: Jul 8, 2021
Applicant: EQUOS RESEARCH CO., LTD. (Tokyo)
Inventors: Keizo ARAKI (Tokyo), Akira MIZUNO (Tokyo), Shota KUBO (Tokyo)
Application Number: 17/263,193